<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>6-表格边框合并</title>
    <style>
        table{
            border-collapse: collapse;
        }
    </style>
</head>
<body>
    <table border="1" width="800px">
        <tr>
            <th>ID</th>
            <th>用户名</th>
            <th>密码</th>
        </tr>
        <tr>
            <td>1</td>
            <td>xml</td>
            <td>123456</td>
        </tr>
        <tr>
            <td>2</td>
            <td>cms</td>
            <td>789056</td>
        </tr>        
    </table>
</body>
</html>